First I optimized p pol PLL frequency when green power is 50mW and optimal frequency is 150MHz.

Today when filter cavity is locked, a strong 70kHz noise appears in CC1 error signal. This makes it difficult to get clean CCFC error signal.

Anyway I measured CCFC error signal again when CC is locked on resonance (Pic. 1).

I found that when demodulation phase of CCFC changed, CCFC error signal also changed from Pic. 2 to Pic. 3.